Circuit controlling device



July 4, 1933. c. T. EVANS CIRCUIT CONTROLLING DEVICE Filed Dec. 7, 1931 Patented July 4, 1933 Umrsnsratas rarest Gems CLARENCE 'r. EVANS, or wnuwarose, w

JLSGOITSEN, ASSIGNUR T 1) CUTLER-HAMMER,

INC OF MILWAUKEE, "WISCOEQTSIN, A QO'RPORATION OF DELAVJARE CIRCUE'IF CONTE-QLLING DEVICE Application filed December '7, 1931.. Serial at. 579,450.

This invention relates to impr vements in circuit controlling devices, and while not limited thereto is particularly applicable to rheostats of the movable crosshead type;

The invention has among its objects to provide a rheostator similar device with a new and improved type of auxiliary contact mechanism which is adapted to cooperate with the main contacts of the rheostat to minimize arcing therebetween.

Another object of the invention is to provide an auxiliary contact mechanism of the aforementioned character which is of simple,

rugged and inexpensive construction and which can be readily removed and reassembled to facilitate inspection or repair thereof.

Another object is to provide an auxiliary contact mechanism of the aforementioned character which is adapted to rotate in a step by step manner to progressively bridge adjacent stationary contacts prior to bridging thereof by the mam contacts.

Various other ob ects and advantages of the invention will herein after appear.

' The accompanying drawing illustrates an embodiment of the invention which will now be described, it being understood that the embodimentillustrated is susceptible of modification without departing from the scope of the appended claims.

In the drawing, Figure 1 illustrates an adaptation of my improved auxiliary contact device to a rheostat of the movable crosshead type.

Fig.2 is an enlarged front elevational view of a portion of the crosshead illus-,.

a rheostat including a crosshead contactor 1 which is movable over the stationary contacts 2 and 8 mounted upon the insulating panels 4 and 5, respectively. The rheostat' may he employ-ed in the control of resistances (not shown) to which the stationary contacts 2 and 3.1nay be connected, whiclrresistanc'es, it maybe assun'ied, are employed for regulating the speed'ofa motor. An airrangement of this general character is disclwed in the patent to 'Reisbach, N o.

'.-.7U9, dated May'Q, 192:2, and hence detailed (iGSCill'JtiOll thereof herein is deemed unnecessary. The crosshead 1 is operated by a screw shaft (5 driven by a pilot motor (not shown), and adapted to be definitely stopped in any one of a number of predeterinincd positions to ellect the desired speed regulation of the aforementioned motor.

The crosshead 1 is provided at each end thereof with a plurality of Contact shoes 7 adapted to slidably engage the stationary contacts 2 and 3, and said shoes are arranged side by side upon a cylindrical rod 8, the endsv of which bear in the lugs 9 and 10 of-the crosshead, as bestshown in Figures l and 5. The bearingopening in each of the con tact is preferably in theform-of a slot, asshown at 11 in Figure 3, to permit movement horizontally of said shoes to conform to'any' slight differences in height between indi'vid ual contacts of the groups 2 and 3, and also to compensate for wear of said shoes. of said shoes isspring pressed against the Each V I shoes 7, which accommodates the rod 8,

stationary contacts by a pair of compression springs 12 and 13 seated within opposed re: cesses in the crossheadx l and in the inner faces of the respective shoes (Fig. 4). .Al-

though the contact shoes 7 are electrically connected to thecrosshead 1 as a result of the manner in which the former are'mechan icallysupported by the-latter, the contact shoes are preferably additionally provided with flexible leads let whichare secured to the crosshead by the binding screws 15.

As shown in Fig. l the crosshead 1 is further provided with the auxiliary contact mechanisms designated in general by the nu- 'merals 16 and 17, the construction of which will be described in detail in connection with the mechanism 17, illustrated in Figures 2, 3, 1 and 5. The mechanism 17 includes a wheel 18 having live bifurcated radial spokes, between the forward ends of the arms of which the roller contacts 19 are rotatably mounted upon pins 20 which penetrate central openings in the respective contacts and aligned openings in the arms of said sp0kes,-the opposite ends ofsaid pins being enlarged or upsetto retain said parts in assembled relation. The wheel 18 is rotatably mounted upon the headed pin 21 which issupported in alined bearing openings in the upper ends of arms 22 and of the lever 21 andis retained therein by a cotter pin The lever Qlis oscillatably mounted upon a pin, 26 supportedwithinbearing openings in'thelugs 27 and 28, of the frame 29. Eaid frameis secured to the undersideof the crosshead 1' by the screws 30. The roller contacts 19 are biased intoengagement with the lateral extensions 39 of the stationary contacts2 and 3 a relatively strong compression spring 31 .which is confined between the lever 24 and the. vertical abutment 32 of frame 29 and is held against lateral displacement by the bosses 33 and 34lformed upon the respective parts. The lever 2 1 is provided with a depending lug 35 adapted to engage an adjustable stop comprising a set screw 36 and a lock nut 87', to limit outward movement of the wheel 18 for a purpose to be hereinafter described. The set screw .36 has threaded engagement with an opening in the depending lug 38 which is preferably formed integrally wlth theframe The auxiliary contact mechanism 16 is "like the mechanisml'l aforedescribed, except that the frame '29 of mechanism 16 is arranged for mounting on the left-hand slde of the cross-head. r

. The lateral extensions 39 of the stationary contacts 2 and 3 which are adapted to, be

engaged by the roller contacts 19 are preferably angularly milled or cut away as shown at 89. p The angular faces 39 form V-shaped pockets when the contacts are mounted adjacent. one another as illustrated inzthe draw- The auxiliary contact mechanisms 16 and 17 are adapted to coonerate with the slidin L 1 b contact shoes 7 in the following manner: As

the crosshead '1 moves upwardly, the wheel 18rotate-to insert the roller contacts-19in the V-shaped' pockets formed by the angular faces 39 to eflectbridging of each pair of stationary contacts slightly in advance of brldging thereof by the sliding contact shoes 7 as best illustrated in 2. The circuit between each twostationary contacts is thus initially completed by the roller contacts 19 and arcing between the contacts 2,78 and the contact shoes 7 is practically eliminated.-

through an arc to approach the V.-shaped I iocket substantiall Y at a ri ht an le to the face of the lateral extensions 8910f the station- Thisis of advantage smce the ary contacts. resultant wear upon the lateral extens1ons39 by the roller contacts 19 is almost entirely lim-' ited to the areas defined by pockets 39. That is to say, the roller contacts 19 move in a direction substantially at a right angle to the face of the extensions 39 to'simultaneously engage the'opposed angular faces .39 of each adjacent pair of stationary contacts 2 or 3 regardless of the degree of wear upon said angular faces. Therefore the instant of bridging engagement by the roller contacts 19 with respect to theinstant of bridging en-i gagement by the sliding contact shoes 7 re mains substantially unchanged regardless of the degree of wear upon the several parts.

During downward movement of the cross-- head 1 the foregoing procedure is reversed the roller contacts 19 lift out of bridging engagement'with the stationary contactssubse' quent to disengagement thereofby the con f tact shoes 7, thus absorbing the arc incidentto breaking of the circuit between each pair of stationary contacts.

' The stop 36 funct1ons to engage the lug 35. when the crosshead reaches its upper or full speed control pos1t1on.- As shown at 40, in

Fig. hthe'stationary contact which provides for full speed control of theaforementioned.

motor dispenses with the extension 39 which includes the angular faces 39 The saving ofmaterial is appreciable in consideration of the fact that contact 40 is usually made relatively wide to obviate the necessityfor perfect spotting or definite positioning offthe crosshead 1. The stop 86 prevents the roller contacts 19 from striking the'panels 4t and 5 when the crosshead- 1 reaches its full speed control position. v v V If it becomes necessa-ry at any time to-replace the wheel 18 because ofworn roller contacts, or for any other reason" removal of said wheel may be effected by merely withdrawing the cotter pin 25 and the bearing pin 21 with which itis associated.

lVhat I claim as new andfdesire to secure by Letters Patent is:

1. In a circuit controlling device, in combination, a plurality of fixed contacts arranged in spaced parallel'relation to each other,za

contactor movable progressively intoand out of bridging engagementwith Successive pairs of said contacts, and an auxiliary contacting device carriedby said contactor and movable therewith, said contacting device comprising a wheel having a plurality of radial spokes,

contactor out of bridging engagement with i the latter.

2. In a circuit controlling device, in combination,v a plurality of stationary contacts having angular edge portions adapted conjointly to form V-shaped pockets between adjacent contacts, a contactor movable progressively into and out of bridging engagement with said contacts, and an auxiliary con tacting device carried by said contactor and movable therewith, said contacting device including a wheel having a plurality of radial spokes and roller contact members rotatably carried adjacent to the outerextremities of said spokes, said wheel beingrotatable dur ing movement of said contactor to progressively insert andv lift said roller'meinbers into 7 and out of engagement with said V-shaped pockets.

3. In a circuit controlling device, in combination, a plurality ofstationary contacts having angular edge portions adapted conjointly to form V-sliaped pockets between adjacent contacts, a contactor movable progressively into and out of bridging engagement with said contacts, and an auxiliary contacting device carried by said contactor and movable therewith, said contacting device including a wheel having a plurality of radial spokes and roller contact members rotat-ably carried adjacent to the outer extremities of said spokes, said wheel being rotatable during movement of said contactor to progressively insert and lift said roller members into and out of engagement with said V- shaped pockets, said wheel being adapted to move said roller members through a path substantially perpendicular to the faces of said stationary contacts.

4:. In a circuit controlling device, in combination, a plurality of stationary contacts having angular edge portions adapted conjointly to form V-sliaped pockets between adjacent contacts, a contactor movable progressively into and out of bridging engagement with said contacts, and an auxiliary contacting device carried by and movable with said contactor, said contacting device including a wheel having a pluralityfof radial spokes and roller contact members rotatably carried adjacent to the outer extremities of said spokes, said wheel being rotatable during movement'of said contac-f tor in one direction to effect insertion of said roller members in'a progressive step by step mannerinto the V=shaped pockets between ad acent stationary contacts prior to bridging engagement thereof by said contactor, said wheel being also rotatable ina reverse direction to efiect withdrawal of said roller members from said V-shaped pockets in'a progressive step by step manner subsequent to disengagement of said contactor from said stationary contactsv respectively.

5; In'a circuit controlling device, ,in combination, a series of fixed contacts arranged in spaced parallel relation to each other, a contactor movable progressively into and out of bridging engagement withlsuccessive pairsof said contacts, an auxiliary-contacting device carriedby and movable with said contactor, said, contacting device including a leveripivotally mounted-upon said contactor, a wheel rotatably mounted adjacent to the freeend of said lever'and having a plurality of radial spokes, roller contact members rotatably carried adjacent to the outer extremities of said spokes, the respective roller contact 'inembers being adapted upon rotationof said wheel in one direction tobe successively inserted into and lifted out of bridging engagement with successive pairs of fixed contacts in advance. of engagement and disengagement of the latter by said contactor, and a spring associated with said lever whereby the roller contact members are biased into engagement with said fixed contacts.

6. In a circuit controlling device, in combination,- a series of fixed contacts arranged in spaced parallel relation to each other, a contactor movable progressively into and out of bridging-engagement with successive pairs ofsaid contacts, an auxiliary contacting device carried by and movable with said contactor, said contacting. device comprising a frame secured to said contactor, a bifurcated lever pivotally carried by said frame, a Wheel rotatably mounted between the arms of said lever adjacent to the free end of the latter, said wheel having a plurality of bifurcated spokes, roller contact members rotatably carried between the arms of said spokes at the outer extremities thereof, the respective roller contact members being adapted upon rotation of said Wheel to be successively inserted into and lifted out of bridging e11- gagement with successive pairs of fixed contacts prior to bridging engagement and dis engagement thereof respectively by said contactor, and a spring adapted to bias said roller contact. members into engagement with said fixed' contacts, said spring being confined between the adjacent surfaces of said lever and'said frame. v r

7. In a deviceof. the character described,

in combination, a series of fixed contacts arranged in spaced relation to each other, a contactor shdable rectilinear-1y to effect bridging engagementthereof with and disengagement thereof from, each pair of fixed contacts progressively, and an auxiliary contacting device coopera'ble with said fixed contacts to minimize arcing between the latter and said contactor, said auxiliary contacting device comprising a star-wheel supported by and movable with said contactor, said wheel having roller members located at each of the outor points thereof, said fixed contacts having 7? ranged in spaced relation to each other,

a contactor-slidable rectilinearly to effect" bridging engagement thereof with anddisengagement thereof from each pair of fixed contacts progress1vely,and an'auxiliary contacting device cooperable with said fixed contacts to minimize arcing between the latter and said contactor, sa d auxiliary contacting device comprising a star-wheelsup'portedby and movable with said contactor, said wheel 1 having roller members located. at each of the outer points thereof, said fixed'co'ntacts having lateral extensions to be engaged bysaid roller members respectively in advance of en gagement of said contacts by saidcontactor upon movement ofthe latter in a given di-- rection, and the-arrangement being such that said rollermembers are disengaged from said lateral extensions 7 subsequent to disengagement of said contactor fromsaid fixed con-= tacts upon movement of-said contactor in the opposite direction.

9. In-acircuit controlling device, incombination, a series of fixed contacts arranged in spaced parallel relation to each other, a

contactor slidably movable rectilinearly to effect bridging engagement thereof with and disengagement thereof from successive pairs of fixed'contacts progressively, and an aux-' iliary contacting device comprising a starwheel supported by and rotatably movable with said contactor, said wheel having roller members located'at each of the outer points thereof, said wheel being operable'to effect bridging by said roller members successively of each pair of fixed contacts prior to bridging thereof by said contactor and to effect disengagement of said roller members succes sively from each pair of fixed contacts subsequent to disengagement therefromzofvsaid contactor, depending upon the'direction of movement of the latter, said wheel and the fixed contacts being arranged in such relation that the respective contacts of each pair are engaged or disengaged substantially s1- multaneously by the roller members associ ated with said wheel.

- In witness whereof, I have hereunto subscribed my name. 1 1

Y CLARENCE T; EVANS.

fee 

